A federal judge in Michigan has upheld the health insurance mandate in the new health care law in a challenge brought by the Thomas More Law Center.

The ruling by Judge George Caram Steeh of Detroit is the first to reject a challenge to the law on the merits, rather than standing or other civil procedure objections, according to the Washington Post, the New York Times and Politico. The case is one of more than 15 legal challenges to the health insurance mandate that takes effect in 2014.

A lawyer for the Thomas More Center, Rob Muise, told the Times that the case is “set up nicely for appeal.”

The nonprofit law center joined with a handful of Michigan residents to argue that opting to forgo insurance is a form of inactivity rather than economic activity. As a result, they claimed, Congress did not have authority to pass the law under the commerce clause.

Steeh disagreed, saying the commerce clause covers not only economic activity, but also economic decisions.

“The decision whether to purchase insurance or to attempt to pay for health care out of pocket is plainly economic,” Steeh wrote. “These decisions, viewed in the aggregate, have clear and direct impacts on health care providers, taxpayers and the insured population, who ultimately pay for the care provided to those who go without insurance.”